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What is CBC?

Updated

A Complete Blood Count (CBC) is a common and comprehensive blood test that evaluates overall health and detects a wide range of disorders, including anemia, infection, and many other diseases. The CBC measures several components and features of the blood, including white blood cells (WBCs), red blood cells (RBCs), and platelets. WBCs are part of the immune system and help fight infections; the CBC measures the total number of WBCs and can also provide a differential count, which breaks down the different types of white blood cells (e.g., neutrophils, lymphocytes). RBCs carry oxygen from the lungs to the rest of the body and return carbon dioxide to the lungs to be exhaled. The CBC measures the total number of RBCs and several related parameters, such as hemoglobin (Hb), hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), and red cell distribution width (RDW). Platelets are small cell fragments that play a crucial role in blood clotting, and the CBC measures the number of platelets as well as additional parameters such as mean platelet volume (MPV) and platelet distribution width (PDW).

The CBC is a valuable diagnostic tool in various clinical settings. Elevated WBC counts can indicate infection or inflammation, while specific patterns in the differential count can help identify the type of infection (e.g., bacterial vs. viral). Low RBC counts, hemoglobin, and hematocrit levels can indicate anemia, while MCV, MCH, and MCHC values can help determine the type of anemia. Abnormalities in the number or appearance of blood cells can indicate blood disorders such as leukemia or clotting disorders. Additionally, CBC parameters can be useful in monitoring chronic conditions like diabetes, cardiovascular diseases, and rheumatic disorders. The CBC is relatively inexpensive, widely available, and provides a broad overview of a patient's hematological health. While the CBC is a powerful tool, it is not specific for any one disease and must be interpreted in the context of the patient's overall clinical picture and other diagnostic tests.

Further Reading:

  1. Zafer Bagci, Ayşe Ruveyda Ugur, & Cüneyt Ugur. (2021). Evaluation of CBC Parameters in Relation to PCR Test Results in Diagnosing Pediatric COVID-19 Disease. Journal of Pediatric Infectious Diseases, 16(06), 278–284. https://doi.org/10.1055/s-0041-1733867
  2. Agnello, L., Giglio, R. V., Bivona, G., Scazzone, C., Gambino, C. M., Iacona, A., Ciaccio, A. M., Lo Sasso, B., & Ciaccio, M. (2021). The Value of a Complete Blood Count (CBC) for Sepsis Diagnosis and Prognosis. Diagnostics, 11(10), 1881. https://doi.org/10.3390/diagnostics11101881
  3. Seo, I.-H., & Lee, Y.-J. (2022). Usefulness of Complete Blood Count (CBC) to Assess Cardiovascular and Metabolic Diseases in Clinical Settings: A Comprehensive Literature Review. Biomedicines, 10(11), 2697. https://doi.org/10.3390/biomedicines10112697
  4. Shahrabi, S., Saki, N., Safa, M., & Pezeshki, S. M. S. (2023). Complete Blood Count Test in Rheumatology: Not Just a Screening Test. Clinical Laboratory, 69(6). https://doi.org/10.7754/Clin.Lab.2022.221012